[eric-engberg]

Fixes #690, and the visible junk the terminal sanitizer (from the escape-injection fix) leaves where it drops an 8-bit sequence's introducer.

What

Color codes written with the 8-bit CSI (U+009B) in place of ESC [ now work like the 7-bit ones:

• The sanitizer keeps them, rewritten as ESC [ … m. Before, it dropped only the U+009B and printed the rest: a command printing \x9b31mred\x9b39m showed 31mred39m.
• Other 8-bit sequences are dropped whole. A CSI that isn't a color (\x9b2J), and OSC, DCS, SOS, PM and APC strings, used to leave their parameters or payload as text. An 8-bit hyperlink with a safe URL is kept, also in its 7-bit form.
• stripSgrCodes removes them (stripSgrCodes leaves C1 SGR styling already supported by the ANSI parser #690). A global foreground override now strips a preserveColors widget's 8-bit colors, and a Custom Command cut by its max width gets its closing reset, so its color no longer runs into what follows.

Why

The ANSI parser has read 8-bit CSI and OSC since #660, so widths already treated these codes as invisible. Two places didn't:

• stripSgrCodes matched only ESC [, which is stripSgrCodes leaves C1 SGR styling already supported by the ANSI parser #690's report.
• The sanitizer added since then removes C1 controls one character at a time. For an introducer, that leaves the sequence's body on the status line: the before stills below show 38;5;161mfeature/login0m where the command printed a pink feature/login. This is worse than stripSgrCodes leaves C1 SGR styling already supported by the ANSI parser #690 describes, because it affects every widget's output, not just the override and truncation paths.

How

• terminal-sanitize.ts:
  • Each 8-bit introducer is read as the ESC sequence it stands for: CSI as ESC [, OSC as ESC ], DCS/SOS/PM/APC as ESC P/X/^/_, with ST (0x9c) ending strings.
  • The kept patterns (SGR and OSC 8) accept either form, and what they keep is written in the 7-bit form, so the rest of the renderer and every terminal see ESC.
  • Anything else is skipped with the same rules as its ESC form. Lone C1 controls that start no sequence (NEL, a stray ST) are still dropped.
• ansi.ts:
  • SGR_REGEX matches ESC [ or 0x9b.
  • restoreBackgroundAfterResets shares the pattern, so its parameter parsing skips the one-character introducer for the 8-bit form.

Demo

A Custom Command with preserve colors running printf '\302\23338;5;161mfeature/login\302\2330m' (\302\233 is U+009B in UTF-8). Line 1 prints it whole; line 2 cuts it to 12 columns.

Powerline

Before (main)	After

Plain

Before (main)	After

Testing

• terminal-sanitize.test.ts:
  • Keeps 8-bit colors and an 8-bit hyperlink, in their 7-bit form.
  • Drops ten 8-bit sequences whole: screen clear, cursor move, CSI b, OSC 52, an OSC 0 title, a hyperlink with an unsafe URL, DCS, APC, PM and SOS.
  • The 8-bit CSI, OSC and DCS entries left the "drops the control character" table, because they now start sequences. The test that pinned the leftover parameters is replaced.
• ansi.test.ts: stripSgrCodes removes 8-bit and mixed color codes and leaves other CSI sequences and hyperlinks alone; restoreBackgroundAfterResets handles an 8-bit reset.
• CustomCommand.test.ts: a truncated 8-bit-colored output ends with a reset.
• renderer-sanitize.test.ts: a widget's 8-bit colors reach the pre-rendered line as ESC [, with the right width.
• bun test: 3125 pass, 0 fail. bun run lint passes.
• Under Node (Vitest): the four changed files pass 113 of 115. The two failures are in CustomCommand.test.ts's cache tests, which spy on os.homedir and fail the same way on main under Node.
• Built CLI (runtime-check.sh, Bun 1.4.2 and Node 26.10.0):
  • With the baseline plain and Powerline configs, identical to main.
  • With the demo configs, both runtimes agree and differ from main as shown above.
  • The TUI opens and exits under both.